An extensive number of antimicrobial compositions are commercially available in liquid or powder form. The liquid compositions typically have active ingredients in the range of 5 percent to 15 percent by weight of the product, but highly concentrated liquid products can contain up to 80 percent active ingredients. Concentrated liquid products must be diluted before use. Ready to use liquid products can have concentrations of active ingredients at least as low as 0.02 percent by weight of the product. All of these liquid products contain significant amounts of water, alcohols and/or other materials as diluents. Because these products are diluted, they utilize more packaging materials and result in higher shipping weights to transport a given amount of active material than is required for a highly concentrated solid.
A significant disadvantage of powder or granular products for commercial applications is that they are not as accurately controllable in dispensing equipment as liquids. Powder systems can require manually scooping a quantity of powder for each use, thus not taking advantage of the ease, accuracy and hands-off labor savings of liquid dispensers. Also, powders can cake if exposed to high humidity or temperatures. Once they become caked, they cannot be easily removed from their shipping container. Non-homogeneous powders can segregate in their shipping containers, in other words, separate or stratify by particle size or density, resulting in a non-uniform mixture that may not be appropriate for ultimate use applications.
Some disinfectants and sanitizers are considered corrosive which creates hazards in shipping and handling. Spilled liquid material from leaking containers or mishandling the product can come into contact with skin or eyes causing tissue damage, pain and discomfort. Powders can create a safety hazard because particles of irritating or corrosive materials can exit their container or become airborne allowing the particles to come into direct contact with tissue, such as skin or lungs, causing burns or discomfort. A solid antimicrobial product would not be easily capable of creating this hazard since it cannot leak out of its container nor can it be spilled in handling.
Because of stringent regulatory controls over disinfectants and sanitizers, especially for institutional uses, solutions for application typically must be prepared with specific and exacting dilution ratios. Typical sanitizer and disinfectant concentrates are mixed with water to obtain a solution with a specific concentration for application. These solutions are used to sanitize or disinfect objects and surfaces such as counter tops, tables, floors, walls, dishes, utensils and fabrics. Many institutions require these products including food processing operations, nursing homes, health care facilities, kitchens, and laundries. Here, the terms disinfectant and sanitizer are used interchangeably to denote an antimicrobial agent even though the terms may have precise and distinct meanings in institutional use and under regulatory control. These products are also effective at deodorizing because they can destroy odor causing bacteria and other microbes.
While liquid and powder products can be measured by hand and accurately diluted, this process is slow and potentially hazardous if the materials are corrosive. Liquid products can be properly diluted using dispensing apparatuses to produce solutions for application, but this does not eliminate all of the inconveniences and hazards of the handling of liquid. Recently, dispensers have been developed for the accurate and convenient dispensing of solids. For example, U.S. Pat. No. 5,342,587 to Laughlin et al. describes a solid dispensing device where the solid is provided in a plastic bottle that is inverted over a bowl. Water is sprayed on the solid to produce a solution that is drained from the bowl.
Some sanitizer or disinfectant concentrates have cleaning agents added to the antimicrobial compounds to create cleaner/disinfectants. Commercially available liquid and powder cleaner/disinfectants clean soils from surfaces as well as kill microorganisms. The cleaning agents in these products are typically alkaline and include anionic or nonionic surfactants along with other additives such as alkaline builders and metal ion sequestering agents. Liquid and powder cleaner/disinfectants have the same disadvantages as liquid and powder forms of other sanitizing products.